Enhanced mechanical properties of silanized silica nanoparticle attached graphene oxide/epoxy composites

The toughening effects of 3-aminopropyltriethoxysilane (APTES) functionalized silica nanoparticles attached graphene oxide (ATGO) in epoxy were investigated. Fourier transform infrared and X-ray photoelectron spectroscopy analysis confirmed chemical functionalization and partial reduction of GO during the functionalization. The nanostructures of GO and ATGO were observed by transmission electron microscopy. The tensile strength and modulus of 1wt.% ATGO-filled epoxy composites at cryogenic temperature (CT) were 29.2% and 22.0% higher than those of pure epoxy. Interestingly, both the tensile strength and modulus of all the composites at CT were significantly higher than those at room temperature (RT). In contrast, impact strength of the composites at RT was higher than that at CT due to the restricted molecular mobility of epoxy. The fracture toughness (K_IC) obtained from the single edge notched bending (SENB) test increased sharply with an increase in ATGO loading in the epoxy up to 1wt.%. The fracture surfaces of the composites analyzed through field emission scanning electron microscopy (FE-SEM) shown the rough surfaces confirming the enhanced impact and tensile properties of the ATGO filled composites.